@pindac Thank you. Trust me, the grin is very much ear to ear at the moment. I am closing in on 50 hrs. and I think it has already opened up and shown what it is capable of. That jives with what a friend who knows this cartridge (non-SL) and the mono version tells me (he uses both to evaluate test pressings professionally).
Interestingly, I also upgraded my subs from a pair of REL R-328 to a pair of S/510 earlier this month, and as they break in more I am enjoying the music that much more.